Syntheses and Crystal Structures of Benzohexathia[7]helicene and Naphthalene Cored Double Helicene

Abstract

Bis(trimethylsilyl)benzohexathia[7]helicene 1, naphthalene cored double helicene 2 (the fused dimer of 1), and a novel ten-membered cyclic diketone with four moieties of dithieno[2,3-b:3',2'-d]thiophene (3) were efficiently synthesized. Their crystal structures were determined with single-crystal X-ray analysis. In their crystal packings, they all show multiple short contacts including intermolecular pi...pi, pi...S, and S...S interactions. UV/vis spectra indicate that significant pi-electron delocalization existed in 1, 2, and 3.

Diastereo‐ and Enantioselective Synthesis of Organometallic Bis(helicene)s by a Combination of CH Activation and Dynamic Isomerization

“…The structure, which was established by using X‐ray diffraction, showed the formation of an organometallic scaffold, in which two octahelicenes shared a common platinum center (Scheme ); such a structure is uncommon because analogues are difficult to obtain by using synthetic organic methods 1. 10…”

Synthesis, Structures, and Properties of π-Extended Double Helicene: A Combination of Planar and Nonplanar π-Systems

“…5 To achieve the π-π overlap, [n]circulenes (n ≠ 6) are required to stack in a one-dimension manner to fit their curvatures completely. [7][8][9][10] Multi-helicity provides plural electronic states and molecular dynamics, and π-extension often causes a dramatic change of electronic structure. Hence, it is important to uncover unconventional molecular packing that maintain π-π stacking, in order to discover the unexplored functionalities of nonplanar aromatic systems in their crystalline state.…”

“…As for conventional helicenes, only partial π-π stacking is usually observed. 3,4,[6][7][8][9][10][11] To add these attractive properties in planar π-systems, proper incorporation of heteroatom and functionalization are often employed. Herein, we report the synthesis, structures, and photophysical properties of π-extended double helicene 1 (C58H28) bearing concatenated two planar tribenzo [b,n,pqr]perylene substructures with fully-conjugated double [6]helicene substructures, a combination of planar and nonplanar -systems ( Figure 1).…”

Synthesis of a Double Helicene by a Palladium‐Catalyzed Cross‐Coupling Reaction: Structure and Physical Properties

“…[2] Recently, double helicenes with various topologies have been synthesized and their physical properties investigated. For example, Cheng and Wang reported the synthesis of double helicene with hexathia [7]helicenec ore. [3] Moreover,T anaka reported aSshaped double azahelicene by meanso ft he Au-catalyzed intramolecular hydroarylation. [4] Recently,H atakeyama and Nakamura reported an interesting Pfused double helicene.…”